Lindman112

New endless TBC is comming out in a few weeks, does the bot work there?
They have their own client you need to download and play from.
Just making sure the bot works with that or if they can detect it

Vendor setup in wrobot will likely work. It's in the advanced settings.
For WotLK, I don't think there's anything besides HumanMasterPlugin that automates buying ammo completely. But it's 20€.
If you're proficient in C#, you can probably change FoodAndDrink plugins (Vanilla, TBC, WotLK - check all 3 plugin sections) to buy ammo instead.

I'm not sure the Wholesome group has anything that does auto vendoring completely, but I would urge you to look into it.
 
Edit: 
They do have auto vendoring now. It does a lot of what HMP also does. I encourage you to check this out. 

You need to use Lua to iterate your debuffs and get their debuff type, then cast Purify if it's poison. 
https://github.com/droidzfr/WRobot_Packages/blob/fccc740c611b6447361d401c2aa35bb401d6f638/Old paid files/akuros/PriestDiscipline By Akuros v1.2.cs#L302

You also need to find the correct parameters for your Wow version. They're different between 1.12.1, 2.4.3, 3.3.5a, 4.3.4, etc